Want To Jack With My Cuz

My cuz is 19 and he is fine he has a nice *** and i want to jack with him so bad but im scared because hes not gay but when i see him sagging it turns me on its even hard for me to get his boxers to smell but all i no he like to smoke weed but i dont maybe if i try to buy him sme and get him drunk he will jack with me but im so scared